Lock washer and method of making same



June 12, 1934. c, oL so 1,963,028

LOCK WASHER AND METHOD OF MAKING SAME Filed Nov. 22, 1933 \\\\\YHIIIIIIIII za FlG.-IO.

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INVENTOR Patented June 12 1934 UNITED STATES PATENT OFFICE Carl G. Olson, Chicago, Ill, assignor to Illinois Tool Works, Chicago, 111., a

Illinois corporation of Application November 22, 1933, Serial No. 699,179

9 Claims.

This invention relates generally to lock washers and methods of making same, and more particularly to lock washers of the overlapping prong is to say, washers of the type wherein a plurality of prongs are disposed along a margin of the annular body and the adjacent marginal portions of each prong overlap in such a manner as to present work engaging edges disposed on opposite sides of the washer body. Thus, when a washer of this type is clamped against a work piece, as by means of a nut or screw head, these overlapping marginal portions ofthe prongs present a firm ratchetlike arrangement of teeth.

It is an object of the present invention to not only provide an improved overlapping washer construction of the type set forth above, but also to provide improved effective methods for producing such washers.

More specifically, the invention contemplates the provision of a washer of the type set forth above, wherein the prongs are of uniform thickness and are thinner than the annular body of .the washer, and to this end I propose to employ 80 a method wherein the portion of the washer blank, which is to be provided with the prongs, is uniformly expanded.

Still more specifically, my invention contemplates a method, as above set forth, which includes the step of undulating the marginal portion of the washer blank to be provided with teeth whereby to cause anexpansion or stretching of the metal, and subsequently severing these undulations in a manner to present, a plurality of prongs which may be conveniently forced into overlapping relation by a simple pressing operation.

The invention also contemplates a method wherein, after the undulating of the blank margin 46 has been completed and the radial severance of said undulations has also been completed, the adjacent margins of the severed sections are forced axially and circumferentially so as to produce the desired overlapping relationship of theprongs.

Afurther object of the present invention is to provide a lock washer and methods of making same, wherein the degree of overlapping is substantially uniform over the entire radial extent of the prongs, whereby the work engaging edge on one side of the Washer is disposed in parallel relationship to the work engaging edge on the opposite side of the washer. 4

The foregoing and numerous other objects and advantages will be more apparent from the following detailed description when considered in connection with the accompanying drawing, wherein- Figure 1 is an elevational view of a lock washer having external prongs arranged in overlapping relation in accordance with the teachings of my invention;

Figure 2 is a fragmentary elevational view similar to Figure 1, disclosing a lock washer provided with internal overlapping prongs;

Figure 3 is a reduced view of an annular washer blank from which my improved overlapping tooth lock washer may be produced; Y

Figure 4 is an enlarged fragmentary view of the lower half of the blank in Figure 3 after the outer marginal section thereof has been undulated;

Figure 5 is an edge view of the undulated washer shownin Figure 4; 4 Figure 6' discloses the washer of Figure 5 after the severance of the undulated sections has been accomplished so as to divide the outer margin into a plurality of prongs; I

Figure '7 discloses the next step of axially and circumferentially forcing adjacent marginal secf8 tions of the prongs into overlapping relationship;

Figure 8 discloses the washer of Figure 7 after the overlapping of the prongs has been completed and each prong straightened;

Figure 9 discloses the manner in which the overlapping margins of the prongs abut each other when the washer is clamped against a work piece; and

Figure 10 is a fragmentary transverse sectional view taken along the line 10-10 of Figure 5 to more clearly illustrate the structural characteristics of the undulations.

Referring now to the drawing more in detail wherein like numerals have been employed to designate similar parts throughout the various views, it will be apparent that my invention contemplates the provision of a lock washer, which includes an annular body 20 of flat spring stock. One margin of the body 20, for example, the outer margin as shown in Figure 1, is provided 105 with a plurality of' prongs 22. Each prong includes what I prefer to call a-central or intermediate normally fiat body portion 24. This body portion 24 of each prong is bounded by marginal sections 26, and thesemarginal sections 26 no r shown in Figure 2.

are arranged in overlapping relation, as clearly shown in Figures 1, 8, and 9. Each marginal section 26 of the prongs presents a work engaging edge 28, which 'is disposed out of the plane of the body 20 and is disposed in substantial parallelism with said body.

It will be clear from Figure I that the degree of overlapping of companion or complementary prong margins 26 is substantially uniform throughout the entire radial overlapping extent thereof. In other words, the same degree of overlapping is presented at the-inner portions of the prong margins 26 of Figure 1 asis presented at the outer portions thereof. Thus, the work engaging edge 28 of one prong margin 26 is parallel with the work engaging edge 28 of its companion or overlapping prong margin. It will be clear, therefore, that the work engaging edges are not only disposed in substantial parallelism with the washer body 20, but each pair of oppositely disposed edges are arranged in parallelism with each other.

Another structural characteristic of my improved lock washer residesin the fact that the prongs 22 are thinner than the body 20. This will be more readily appreciated from the description of the method of manufacture about to be given. In practicing my improved method of washer manufacture, I propose to first produce annular washer blanks, designated by the letter A in Figure 3, from suitable sheet or strip stock. To provide a lock washer having external prongs of the type shown in Figure 1, I then subject the outer margin of the blank A to a forming operation so as to present a plurality of radial undula tions having crests B on one side and crests C on the opposite side of the washer body. This undulating process obviously stretches the outer margin of the blank, thereby causing a uniform thinning of the stock. The crests B are then severed by radially slitting the stock, as clearly indicated in Figure 6. The marginal sections 26 of the prongs are then shifted axially and circumferentially as indicated in Figure '7, and finally each prong is flattened and positioned in overlapping relation with respect to the next adjacent prong as indicated-in Figure 8. Obviously, when the washer is clamped against a work piece, the marginal prong sections 26 are moved into abutting relation as clearly shown in Figure 9,

thereby presenting a rigid ratchet tooth construction.

From the foregoing it will be apparent that the undulating, severing, and ,final forming operations, as set forth above, may be performed by the use of suitable dies, punches, and the like. It will also be noted that in practicing the above described method, it is not necessary to reduce the internal diameter of the annular stock. In other words, the overlapping of the prongs is produced without varying said internal diameter.

The above described method may also be practiced in the production of internal prongs 22a To produce such prongs it is only necessary to undulate the inner margin of the body portion 2011 instead of the outer margin. In the formation of either internal or external overlapping prongs, the expanding or stretching of the metal takes place to produce a prong of uniform thickness, which is thinner than the main annular body of the washer. lBy practicing my improved method, the metal is not subjected to distortion, which would permanently deform the molecular structure and hence would impair the strength of the stock. My method is ipeaoas I undulating process, but this does not impair its locking qualities, nor tend to introduce fractures.

It will also be noted that the inner ends of the undulations gradually'merge into the plane of the body 20, as clearly shown in Figure 10. Curved portions E and F, designated in Figure 10, cause a blending or juncture of the prong and body sections of the washer stock without introducing permanent distortions, fractures, etc., which might occur in the event that sharp corners and the like were present. Thus, the tool employed to produce the undulations should be carefully formed so as to avoid the presence of defects mentioned above. Having the degree of overlapping substantially uniform throughout the radial extent of the prong positively counteracts any tendency for the marginal edges of adjacent sections 26 to bind. Furthermore, a very rigid abutment of uniform strength is provided from one end of the overlapping to the other. From the foregoing description it will also be apparent that, in practicing the steps of stretching, slitting, and forming, the prong sections areexpanded only in a circumferential direction. That is to say, the metal which is waved or undulated, is not. expanded diametrically or radially, all of, the expansion taking place circumferentially and hence utilized to cause the radial edges or segments of prongs to overlap in successive operations.

Obviously the form of undulations and the l ke disclosed herein may be modified and the steps of the described methods varied without departing from the spirit and scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A look washer including an annular body portion formed from fiat spring stock and a plu- I20 .work engaging edges on opposite sides of and spaced from the washer body, the degree of overlap being substantially uniform over the entire radial extent of the prong, whereby to present uniform abutting relationship when the washer is clamped against a work piece.

2. A lock washer including an annular body portion formed from flat spring stock and a plurality of prongs formed along at least one margin of said body portion, adjacent margins of said prongs disposed in overlapping relation so as to present work engaging edges on opposite sides of and spaced from the washer body, each. prong having a thickness which is uniformly less than the thickness of the original stock of the washer body, the overlap of the prongs serving to present abutting relationship of said prongs when the washer is clamped against a Work piece.

3. A lock washer including an annular body portion formed from fiat spring stock and a plurality of prongs formed along at least one marpresent work engaging edges on opposite sides of and spaced from the washer body, the degree of overlap being substantially uniform over the entire radial extent of the prong, .whereby to present uniform abutting relationship when the washer is clamped against a work piece, said work engaging edges being parallel with the plane of the washer body.

4. The method of forming lock washers including the steps of forming undulations along at least one margin of an annular washer blank, severing said undulations so as to present a plurality of marginal'prongs, and then axially and circumferentially shifting adjacent. margins of the prongs into overlapping relationship.

5. The method of forming lock washers including,the steps of forming undulations along at least one margin of an annular washer blank, severing said undulations so as to present a plurality of marginal prongs, and then axially and circumferentially shifting adjacent margins of the prongs into overlapping relationship without affecting the diametrical dimension of the washer.

6. The method of making lock washers which includes the steps of circumferentially stretching and radially severing the stock along at least one margin of the washer to provide a plurality of radial prongs along said margin which are thinner than the annular body of the washer, and circumferentially shifting adjacent margins of the prongs to cause said margins to be disposed in overlapping relation, the diametrical dimension of the washer being maintained substantially constant.

7. The method of making lock washers which includes the steps of forming an annular washer body from resilient flat stock, and forming a plurality of overlapping prongs along at least one margin thereof by circumferentially expanding at least one of the radially extending margins of the washer and radially severing said margin to permit the expanded stock to be overlapped in the vicinity of said severances.

8. The method of making lock washers which includes the steps of providing an annular washer from resilient fiat stock, warping at least one margin of the washer to effect a circumferential stretching thereof, radially severing said stretched margin, and causing the sections of said margin in the vicinity of said severances to 

